Influence of incisor position control on the mandibular response in growing patients with skeletal Class II malocclusion.

INTRODUCTION: This study aimed to test whether control in maxillary and mandibular incisor position, during treatment with an acrylic splint Herbst appliance, could influence the mandibular response in growing patients with skeletal Class II malocclusion. METHODS: The lateral cephalograms of 61 patients (mean age, 12.3 years; standard deviation, 1.6) with skeletal and dental Class II malocclusion were retrospectively analyzed both at baseline and after Herbst appliance removal, using a modified Pancherz cephalomeric analysis. Forty-five patients had received miniscrew in the mandibular arch to control mandibular incisor anchorage. In 21 patients, the maxillary incisors had been proclinated before starting the treatment for deepbite and maxillary incisor lingual inclination. All the patients were categorized a posteriori into 2 homogeneous groups, according to dental overjet reduction: 30 patients with dental overjet reduction (DR) and 31 patients without dental overjet reduction (NDR). RESULTS: Both groups presented a significant skeletal correction. However, the change was significantly greater in the NDR group than in the DR group (P <0.01). The mandibular bone base reached a median value of 4.0 mm (interquartile range, 2.5) in the NDR group vs 1.1 mm (interquartile range, 2.8) in the DR group (P <0.001). The 2 groups were also significantly different in terms of the positional change of maxillary incisor, which was proclinated in group NDR and lingualized in group DR (P <0.001). CONCLUSIONS: The results showed that dental control of overjet was beneficial to improve the effectiveness of Herbst treatment in increasing mandibular length in growing patients with skeletal Class II malocclusion.

Upper canine response to rapid maxillary expander anchored to deciduous vs. permanent molars.

PURPOSE: To understand whether two different designs of Haas-type rapid maxillary expander (H­RME) might have a different influence on canine eruption. PATIENTS AND METHODS: In all, 108 subjects seeking orthodontic treatment were selected and divided into two groups-H­RME with bands on the upper second deciduous molars (GrE), H­RME with bands on the upper first permanent molars (Gr6)-and were also compared to an historical untreated control group (CG) of 29 subjects. Panoramic x­rays (OPG) were performed before and after RME (T0-T1: 16 ± 7 months) and the upper canine angulation to the midline ("α" angle) was measured on both pre- and posttreatment OPG. RESULTS: A significant improvement of the canine position (decrease of the α angle) following RME in subjects with mixed dentition was reported in both treated groups, although the different design of the RME did not significantly affect canine angulation. Canine angulation in untreated subjects with transversal discrepancy did not improve significantly. CONCLUSION: Using RME in the early mixed dentition appears to be an effective procedure to increase the rate of eruption of maxillary canines, but the position of the bands on the upper second deciduous molars or on the upper first permanent molars and the significant different expansion of the upper dental arch at the canine level does not significantly influence the canine angulation following early treatment therapy.

Lingual mandibular osteonecrosis after dental impressions for orthodontic study models.

A 43-year-old man sought orthodontic treatment to close anterior diastemas. During the impression procedure for routine documentation, the orthodontic assistant exerted excessive pressure on the metallic tray; 2 days later, the patient reported the detachment of a small piece of mucosa overlying the mylohyoid crest and was referred to a maxillofacial surgeon with a diagnosis of lingual mandibular osteonecrosis. The etiology of bony osteonecrosis is discussed, together with the anatomic variations that can be present in the basal bone and that must be carefully checked before an impression is taken.

Comparison of complications in the conventional telescopic Herbst rod and tube and Manni telescopic Herbst: A retrospective clinical study.

OBJECTIVES: To compare the prevalence of clinical complications between two different telescopic Herbst systems: the conventional telescopic system, with traditional rod and tube (RMS), and the Manni telescopic Herbst appliance (MTH). MATERIALS AND METHODS: Ninety subjects treated with RMS were compared to 89 patients treated with MTH. All of the complications that occurred were reported, and percentages of prevalence were calculated. RESULTS: MTH showed a significantly lower percentage of reversible complications (that did not require appliance removal) when compared to the reversible complications during RMS treatment (20.2% vs 51.1%). No statistically significant differences were found between RMS and MTH regarding irreversible complications (that required appliance removal and full re-make). All of the irreversible complications occurred after reversible complications in the RMS group, while most of the irreversible complications in the MTH group occurred without any previous reversible complication. CONCLUSIONS: MTH exhibited a smaller number of clinical complications during Class II skeletal malocclusion therapy.

Cephalometric and dental arch changes to Haas-type rapid maxillary expander anchored to deciduous vs permanent molars: a multicenter, randomized controlled trial.

OBJECTIVE: To assess radiographic changes and dental arch changes with Haas-type rapid maxillary expansion (H-RME) anchored to deciduous versus permanent molars in children with unilateral posterior crossbite. METHODS: In all, 70 patients with unilateral posterior crossbite were randomly allocated to group GrE (H-RME on second deciduous molars) or Gr6 (H-RME on first permanent molars) and compared between T0 (before treatment) and T1 (at the RME removal; i.e., 10 months after the end of the activation of the screw). At T0 and T1, cephalometric head films were digitally traced, dental casts were scanned, and rotations of the upper first molars, of the upper central, and of the upper lateral incisors on the models were measured. RESULTS: Between T0 and T1, the cephalometric analysis showed a significant decrease of the angulation of the upper central incisors to the SN line and to the palatal plane in GrE together with a significant increase of the lower incisors to the mandibular plane (IMPA). The digital dental cast analysis showed that the central and lateral incisors mesiorotated significantly more in GrE than in Gr6. Patients in GrE also showed a statistically significant distorotation of the upper first permanent molars after RME. CONCLUSIONS: GrE showed a significant and spontaneous retraction and alignment of the upper central and lateral incisors compared to Gr6. This is probably due to a more pronounced expansion in the anterior area and more accentuated pressure of the upper lip in GrE. IMPA increased significantly in GrE vs Gr6. GrE also showed a more significant distorotation of the upper first permanent molars compared to Gr6. This is probably due to the design of the H-RME in GrE, where the screw is more anteriorly positioned and the bands are absent on the upper first permanent molars which are, therefore, free to adapt to the best occlusal situation. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02798822.

Dental arch response to Haas-type rapid maxillary expansion anchored to deciduous vs permanent molars: A multicentric randomized controlled trial.

OBJECTIVE: To assess maxilla and mandibular arch widths' response to Haas-type rapid maxillary expansion (RME) anchored to deciduous vs permanent molars on children with unilateral posterior crossbite. MATERIALS AND METHODS: Seventy patients with unilateral posterior crossbite recruited at the Universities of Genova, Siena, and Insubria (Varese) were randomly located into GrE (RME on second deciduous molars) or Gr6 (RME on first permanent molars) and compared. RESULTS: Upper intermolar distance and permanent molar angulation increased significantly in Gr6 vs GrE at T1. Upper intercanine distance increased significantly in GrE vs Gr6 at T1 and T2. GrE showed significant increases for upper intermolar and upper intercanine widths. Gr6 showed statistically significant increases for upper intermolar widths, for upper and lower intercanine widths, and for increases of angulation of upper and lower permanent molars. CONCLUSIONS: GrE showed reduced molar angulation increases at T1 and reduced molar angulation decreases at T2 when compared with Gr6. At T2, the net increase of the upper intercanine distance in GrE was still significant compared with Gr6, indicating a more stable expansion in the anterior area.

A computerized photographic method to evaluate changes in head posture and scapular position following rapid palatal expansion: a pilot study.

OBJECTIVE: To assess the applicability of a computerized method to measure on digital photographs the changes in head and scapular posture following rapid palatal expansion (RPE) treatment. STUDY DESIGN: Randomized controlled trial. Twenty-three children (age 9.2 +/- 70.88 years) diagnosed with maxillary constriction were randomly divided into two groups: 1. Study group (n = 12): patients receiving RPE treatment; 2. Untreated controls (n = 11). Postural measurements were taken on frontal, lateral, and dorsal views of each subject. In the study group measurements were taken at T0 (the day orthodontic records were taken), T1 (end of RPE active phase), and T2 (RPE removal). In controls the same observations were conducted at T0 and T1(98.18 +/- 36.01 days after T0). Measurements were statistically analyzed (Intraclass Correlation Coefficient, t-tests, Signed Rank test, One-Way Repeated Measures Analysis of Variance, Tukey test; p < 0.05). RESULTS: In the study group a significant reduction in forward head posture (FHP) occurred between T0 and T1. Forward shoulder posture (FSP) decreased significantly between T1 and T2. At T1 treated patients exhibited significantly lower values of the measurements indicating FHP and FSP than controls. CONCLUSION: Changes in head and scapular posture following RPE treatment can be documented with computerized measurements on digital photographs.